The phrase "to leak out" means to become known or revealed, often without intention. It can refer to information being shared inadvertently or accidentally, such as when a secret is unintentionally disclosed by someone who wasn't supposed to reveal it. The term also applies to physical objects that escape their intended containment and are released into the environment, such as liquid spilling out of a container. In essence, "to leak out" means for something to become known or revealed without proper control or restriction.